1. Field of the Invention
The invention relates to apparatus for transporting light loads (10 to 15 kg) placed in containers conveyed by self-propelled carriages on rails.
2. Description of the Prior Art
Generally, different apparatus of this kind have already been proposed.
Thus, in a first type of apparatus, known particularly from the patent U.S. Pat. No. 4,015,537, the containers are fixed permanently to the self-propelled carriages.
In this case, the carriages may be equipped with mobile sliders memorizing the receiving station. So that such installations operate correctly, the stations must have permanently available a number of carriages which are pre-assigned to them. For this, the receiving stations must return them imperatively to the sending station in the shortest possible time. This is a major drawback resulting in the jamming of the installations if the rules for working are not complied with.
Of course, with the transport apparatus driven by computer, the self-propelled carriages may be provided for two-way working. In this case, the stations no longer have pre-assigned carriages. They are parked in parking zones provided for this purpose at different positions in the installation. A station wishing to make a dispatch calls a self-propelled carriage with empty container and, after loading, dispatches it. The receiving station must unload the carriage in the shortest possible time and send it back to a zone for parking carriages with empty containers.
Thus, in the two above types of apparatus, the receiving stations, since they do not dispatch carriages, are very quickly saturated. This situation reduces the performances and results rapidly in jamming of the installation.
Another type of apparatus divulged particularly by the German patent DE 33 08778 provides removable containers which can be locked on the self-propelled carriages. However, the drawback of this solution resides in the fact that in order for the installation to be able to operate correctly, the user must be present at the time when the self-propelled carriage penetrates into the station, either for loading it or for unloading it, so that it may be used rapidly again for another mission. To overcome this drawback. The patent GB 2 194 498 provides an automatic loading/unloading station in which the containers are engaged on the carriages transversely to their axis of movement. However, such an installation requires relatively complex and expensive loading/unloading stations.